FUNGI IMPERKECTX (dEUTEROMYCETES) 



261 



groups of ASCOMYCETALES. Four families are included in this 

 order, and these families include a considerable number of important 

 genera of fungi, which specifically are the cause of important plant 

 diseases. Phyllosticta is a genus, the species of which are confined to 

 leaves, and they produce characteristic leaf spots on a great variety of 

 plants. The specific name of the fungus is usually derived from that 

 of the host plant attacked, as for example, Phyllosticta catalpa, which 



Fig. 103. — Six j3en Davis apples showing apple blotch {Phylloslica solilaria). 

 (After Scott, W. M., and Rarer, J. B., Bull. 144, U. S. Bureau of Plant Jnduslry. 

 March 6, 1909.) 



grows on the leaves of the catalpa. The group has been monographed 

 systematically by J. B. Ellis. The spores are small, egg-shaped or 

 elongated, unseptate and in color pale green, or hyaline, produced in 

 pycnidia. The most important species of this genus are Phyllosticta 

 ampelopsidis on the Virginia creeper (A mpelopsis) ; catalpm on catalpa 

 leaves; labrusccB on the leaves of the grape; pavicB on horse chest- 

 nut leaves (Fig. 102); Phyllosticta solilaria E. and E. (Figs. 103 and 

 104) is the cause of apple blotch, and violm on violets. The conidio- 



